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Hybrid Single and Multiobjective optimization for Engineering Design without Exact Specifications
Get PDFA challenge in engineering design optimization is that sufficient information may not be available to define the exact specifications beforehand. While iterative trial optimization using different specifications is widely used in industry, multiobjective optimization is attracting much attention in the academic field. However, off-the-shelf methods in both categories are time-consuming due to the involved computationally expensive simulations. In this paper, the characteristics of the targeted problem are summarized; the gap between off-the-shelf methods and the practical need is then analyzed. A simple yet effective framework, called two-stage multi-fidelity surrogate model-assisted optimization (TMSO), is proposed to improve efficiency. TSMO is implemented by two state-of-the-art optimization algorithms and two real-world design cases demonstrate its effectiveness in practice. The research topics in multiobjective optimization and surrogate model-assisted optimization inspired by the TSMO framework is finally discussed
Framing the Conversation: The Role of the Exhibition in Overcoming Interdisciplinary Communication Challenges
Get PDFThe role of the exhibition in overcoming interdisciplinary communication challenges is explored. The meaning of interdisciplinary communication is established, alongside the challenges it brings, where their route causes lie and the extent to which the exhibition is equipped to address them. It concludes that exhibitions of a particular nature are uniquely equipped to facilitate better quality interdisciplinary communication in certain contexts, but that further work is needed to develop mature curatorial models to facilitate this. A structure for such models is proposed, alongside the steps that now need to be followed if exhibitions are to fulfil this untapped potential at the interface of art and technology
Numerical design and optimisation of a novel heatsink using ANSYS steady-state thermal analysis
Get PDFThis paper presents a numerical study of thermal performance on heatsink configurations for power electronic devices. The analysis was based on numerical modelling using the CFD software ANSYS 19.1 Steady-State Thermal. The heatsink geometrical features are investigated and compared with each other. The effects of material selection, total surface area, temperature uniformity and maximum surface temperature are assessed. The increase of surface area, implementation of geometrical features, and high thermal conductive material was found to reduce the maximum surface temperature and improve overall thermal dissipation capacity. With a constrained base (50mm × 50mm × 5mm), the novel designs incorporating secondary branches lead to best thermal performance, achieving up to 50% improvement in thermal efficiency. It was concluded that the implementation of nature inspired geometrical features and material configuration, studied in this work exhibits significant benefits for applications in heatsink for electronic devices
Visualization of integrated indicators of information risk in decision support systems
Get PDFDecision-making is one of the essential functions of any manager. The means of visualization play a crucial role in supporting the manager in the decision-making process. This paper discusses the visualisation of information risks based on integral indicators. It provides a description of a mathematical model of the method of dynamic meta-anamorphosis and an example of its practical implementation. The advantages of using a hybrid approach to the development of dynamic meta-anamorphosis are discussed
Experiences of young people with harmful sexual behaviours in a residential treatment programme: a qualitative study
Get PDFThis qualitative study aimed to explore the experiences of young men who have previously participated in a residential treatment programme based in North Wales for harmful sexual behaviours. In-depth interviews with 25 young men aged between 15 and 33 were conducted and thematically analysed. Findings highlight some key strengths of the treatment programme including building quality relationships with staff and the community and the learning of life skills that are also later employed to manage risk of sexual and non-sexual offending. The study supports recent research [Balfe, M., Hackett, D., Masson, H., & Phillips, J. (2019). Experiences of young people with harmful sexual behaviours in services: A qualitative study. Journal of Child Sexual Abuse, 28(6), 649–666. https://doi.org/10.1080/10538712.2019.1573390] that more social and psychological supports need to be available for young people post-treatment while in a period of transition and liminality. Finally, the study further supports other research [de Vries Robbe, M., Mann, R. E., Maruna, S., & Thornton, D. (2015). An exploration of protective factors supporting desistance from sexual offending. Sexual Abuse: A Journal of Research and Treatment, 27(1), 16–33. https://doi.org/10.1177/1079063214547582] in that emphasis should be placed on social, interpersonal, and environmental protective factors rather than psychological ones alone
Preventing homelessness among women prison leavers in Wales
Get PDFUnder the Housing (Wales) Act 2014, prison leavers are among those who are no longer considered a priority need. This paper draws on interviews conducted with 17 women prison leavers and ten professionals that formed part of a Welsh Government funded evaluation of homelessness services to adults in the secure estate. The findings in this study lend support to previous research that indicates women who come into contact with the criminal justice system often have multiple and complex needs. The need for gender specific services and more availability of supported accommodation to ensure the effective resettlement of women prison leavers is also identified
Efficient Design Optimization of High-Performance MEMS Based on a Surrogate-Assisted Self-Adaptive Differential Evolution
Get PDFHigh-performance microelectromechanical systems (MEMS) are playing a critical role in modern engineering systems. Due to computationally expensive numerical analysis and stringent design specifications nowadays, both the optimization efficiency and quality of design solutions become challenges for available MEMS shape optimization methods. In this paper, a new method, called self-adaptive surrogate model-assisted differential evolution for MEMS optimization (ASDEMO), is presented to address these challenges. The main innovation of ASDEMO is a hybrid differential evolution mutation strategy combination and its self-adaptive adoption mechanism, which are proposed for online surrogate model-assisted MEMS optimization. The performance of ASDEMO is demonstrated by a high-performance electro-thermoelastic micro-actuator, a high-performance corrugated membrane micro-actuator, and a highly multimodal mathematical benchmark problem. Comparisons with state-of-the-art methods verify the advantages of ASDEMO in terms of efficiency and optimization ability
Design and Optimization of a Slotted Monopole Antenna for Ultra-Wide Band Body Centric Imaging Applications
Get PDFThis paper presents a cost-efficient design, optimization and physical implementation of a compact slotted ultrawideband (UWB) monopole antenna for body-centric imaging applications. The proposed antenna is initially modelled and designed with the aid of commercial software (CST-Microwave Studio). To ensure that the proposed design is meeting the required specifications with reduced design time, the parallel surrogate model-assisted hybrid differential evolution for antenna optimization (PSADEA) is proposed to optimize the design. Based on the best set of geometry parameters for the optimum antenna performance, the antenna prototype is realized on an FR-4 substrate and analyzed in terms of bandwidth, gain, efficiency, and radiation pattern with and without the tissue models. All measured results are found to be in good agreement with the simulated results. The antenna provides a good reflection coefficient (S11 <-10 dB) in the UWB frequency band from 3.1 GHz to 10.6 GHz and maintains its bandwidth UWB operation without detuning when placed in closed contact with the human body or breast mimicking tissues (phantoms)
Characterization of the polysaccharide from cola millenii seeds
Get PDFWe have isolated and characterized a water soluble polysaccharide from Cola millenii seeds. It was found to be composed of a total of 59% neutral sugars (mainly rhamnose, galactose and arabinose ~ 24, 13 and 8% respectively) and 41% uronic acids [mainly galacturonic acid]. The weight and number average molar mass values were found to be 4.7 x 106 g/mol and 3.5 x 106 g/mol, respectively. The polysaccharide exhibited polyelectrolyte properties with the intrinsic viscosity varying with salt concentration. The polysaccharide formed a highly viscous solution in water with apparent zero shear viscosities of 0.59 - 772 Pa.s at concentrations 0.3 - 2.5wt%. The solutions were shear thinning even at very low concentrations. The mechanical spectra showed gel-like characteristics at concentrations >2 wt%. The rheological behavior indicates the polysaccharide has potential for application as a thickener and suspending agent in food, pharmaceutical and cosmetic formulations